Unable to establishing link between two routers with different subnet

[kasulasaiganesh]

I have two ISR 4351 routers and I'm trying to  esatliblising connectivity between 2 routers with serial interface. Is it possible to connect with different subnets?

R1# serial 0/0/0 

ip address 192.168.1.1/24

encapsulation ppp

R2# serial 0/0/0

ip address 192.168.2.1/24

encapsulation ppp

[MHM Cisco World]

It p2p so you can not use different subnet in each side.

MHM

[kasulasaiganesh]

Do you have any idea about it. Is there any feature or else i can go with any  technology ? like MPLS 

[MHM Cisco World]

I already mention below how you can use lo as ip unnumbered and make p2p use different subnet

Can you more elaborate why you need different subnet in each side?

MHM

[M02@rt37]

Hello @kasulasaiganesh 

No, you need same subnet between these two serial interfaces. Aslo, from one side, you need to configure a clock [edited] if HDLC configured.

https://linuxtiwary.com/2015/03/30/static-routing-configuartion-on-cisco-router-using-serial-port/

[MHM Cisco World]

One case you can use different subnet but it so so limit

R1 

LO0 1.1.1.1 

Interface x

Ip unnumbered loopback 0

R2 

LO0 2.2.2.2

Interface x

Ip unnumbered loopback 0

Here even if lo use different since it p2p you can use different subnet with unnumbered ip address 

But again it so limit and have some restrictions

MHM

[kasulasaiganesh]

Ok i'll try this configuration and update you. 

thank you

[kasulasaiganesh]

Hi

clock? is this command to establish link with different subnets.  

[M02@rt37]

@kasulasaiganesh 

With PPP encapsulation, the clock rate command is not required. PPP does not rely on a specific clocking signal from the DCE side. The clocking is often negotiated dynamically, and PPP handles synchronization differently than HDLC.

So:

R1# serial 0/0/0 

ip address 192.168.1.1/24

encapsulation ppp

R2# serial 0/0/0

ip address 192.168.1.2/24

encapsulation ppp

[Joseph W. Doherty]

"With PPP encapsulation, the clock rate command is not required."

Are you sure?  Reason I ask, Cisco shows an example of two routers, back-to-back serial, using PPP and clockrate.  See PPP Configuration Example in https://www.learncisco.net/courses/icnd-2/wan-technologies/serial-encapsulation.html.

[Joseph W. Doherty]

No, "clock(ing)" is needed on serial links to work.  Normally provided by the DCE.  If you have to routers back-to-back, one of them needs to provide it.

[balaji.bandi]

Hope these are physical kit, how are you connecting these Serial port ?

Look at the high level you interface IP address wrong - correct this and test it :

R1# serial 0/0/0

ip address 192.168.1.1/24

encapsulation ppp

R2# serial 0/0/0

ip address 192.168.1.2/24

encapsulation ppp

[Joseph W. Doherty]

An interesting question.

@MHM Cisco World has already showed one way to do this indirectly.

Normally, explicit IPs on both ends would be within the same subnet.  But I wonder whether it might work with a static route on each router with the far side interface network being reachable through the local router's serial interface.

[kasulasaiganesh]

Before I have tried with default route. Yes! route was formed but there is no end to end communication. 

[Joseph W. Doherty]

What's the actual default route statement look like?

You also did the similar on R2?